A glass processor in southern Taiwan had been sealing panel edges with a conventional electric furnace — long cycle times, heavy power draw, and uneven heating at the edges. After switching to an infrared emitter whose wavelength was chosen to suit the process, it heated up faster and the temperature was easier to control, and both yield and throughput climbed. The real strength of infrared heating is that it can be configured to fit the process — the same emitter, placed in a different industry with a different wavelength, can do something completely different. First, the basics of the wavebands: infrared is generally divided into short-wave (about 0.78–1.5 microns), medium-wave (about 1.5–3 microns) and long-wave (above 3 microns). Short-wave penetrates deeply and heats quickly, making it good for heating a material uniformly all the way through, whereas medium-wave is mostly absorbed at the material’s surface layer and heats the surface. So the core of selection is matching the emitter’s wavelength to the absorption characteristics of what you are heating.
Glass: tempering and bending
Glass and its coatings absorb certain short-wave infrared well and can be heated deeply and quickly, which is why it is commonly used for glass tempering, hot bending and edge sealing. In practice, you first analyse the spectral characteristics of the coating and the glass substrate, then pick the matching peak wavelength (for glass-coating applications, a peak wavelength of around 1.15 microns has been used). Because the temperature is precisely controlled, cycle times shorten dramatically and yield improves, and it also uses less energy than a conventional furnace.
Automotive: paint curing and lamination
It is used for headlamps, interior PVC lamination and powder-coat curing on alloy wheels; a medium-wave to carbon medium-wave setup cures the coating evenly and reduces sagging and colour variation. And because infrared switches on and off quickly, the line’s takt is easy to control, saving the warm-up time and floor space of a long conventional oven.
Textiles: coating and drying
Drying after fabric coating, impregnation and printing or dyeing depends heavily on how efficiently moisture and solvents are driven off, and medium-wave is well absorbed by water and solvents, removing moisture quickly without damaging the fabric — which is why continuous lines often rely on it to push throughput. Screen-print curing on T-shirts and fabric is another classic application.
Metals and medical materials
Metal annealing and pre-heating commonly use short-wave (fast, deep penetration and high efficiency), while hot-pressing and forming of thermoplastics such as medical nonwovens and PP lean towards medium-wave, concentrating the heat in the surface layer to avoid over-heating and distortion. Even though it is all “heating,” picking the wrong waveband can mean twice the effort for half the result — or even damage the material outright.
The best wavelength, power density, emitter layout and distance differ for every process — there is no one-size-fits-all answer — so TingHao starts by understanding your heating target, line speed and space constraints, then plans a suitable configuration and selection. We serve manufacturers across Kaohsiung, Tainan, Pingtung and the wider southern Taiwan. Call 07-363-0802 to discuss your heating process with TingHao Technology.